I am somewhat new to landscape shooting. My usual haunts are sports and birds, with a little macro thrown in. However, I am planning a 3 day hike through Kings Canyon NP next summer with my sons. I hope this will be a very special outing (and unusual...I haven't done much hiking/backpacking), and I want to memorialize it with some great photos, including shots of the night sky...the Milky Way arcing above an Alpine lake, etc... Not so much interested in star trail shots, but more "as seen" night skies.

I am currently shooting a 7D, but am planning on picking up a 6D or 5Diii over the coming weeks, most likely with a 17-40.

I am looking for advice on night sky photography in general, and on lenses in particular. For weight reasons I am looking to take a max of two lenses with me - the aforementioned yet-to-be-purchased 17-40, and potentially one other fast prime for night skies. I will also be picking up a lightweith tripod (any suggestions?)

The fast primes I now have are the 28 1.8, 50 1.4, and 100 2.0. I would consider picking up a 50 1.8 and taking that, for its low weight if it made sense. Obviously these lenses have different fields of view and I will need to figure out how wide I want to go, but that aside, I am interested in what FM landscape shooters think of these lenses as potential night sky tools. Or do I even need them for this application on a 6D or 5Diii if I am taking a 17-40? And, is it better to shoot these lenses wide open, or stop them down a bit, living with a slower shutter speed (with consequent star trailing) or higher ISO (noise). Are there other lenses I should consider? I am not keen on a 50 or 85 1.2 for both cost and weight reasons...

In terms of general technique, I read in some FM post that I can't now find a rule of thumb about star shooting that said that to effectively eliminate star trails, the shutter speed should be no more than (600/focal length) seconds. So I'd be looking at 10 second at 60mm for examle. Is this about right? And I assume this is for FF, and would need to be adjusted (reduced) by the crop factor on my 7D.

It sounds like a fun trip you have planned. For the star shots, typically wider is better. While I have seen some cool shots with a longer lens, if you want to shoot stars over an alpine lake you need to be shooting wide enough to take the lake in.

My suggestion is to just use the 17-40mm for the stars and shoot at 17mm. Personally, I would throw the rule of thumb out the window, basically with shooting wide, you don't want to shoot any longer than 30 seconds, if you can keep it at 25 secs that would be great.

If you are able to get the 5Diii, then that helps with the idea of needing a faster lens. Course with my Nikons I have been shooting stars just fine at f4 for years now, I am sure you will be fine with that too.

A couple keys to shooting stars and especially when you want something in the foreground like a lake. First thing is know how difficult it is to focus in the dark, it's hard... so what I would suggest is while it's still light out, go set up your camera on your tripod and compose a nice view of the lake with lots of sky in the shot, focus it in broad daylight, take a shot, make sure it's in focus. Mark down what the focus is, if you are doing this close to sunset, you can get some duct tape and tape the focus ring down even so it can't move. Then wait for night, or shoot through the twilight.

Exposures, I already mentioned f4, my basic settings when shooting stars is ISO 3200, 25 sec at f4. Take a shot, check the histogram, don't necesarily believe the histogram. Of course the histogram will be heavy to the left, there is a lot of dark sky there, but you don't want it all the way to the left either. So based on your first shot, if you can back down on the ISO because it's too bright, go ahead. But if it's looking a bit dark, perhaps the lake isn't showing up much and the sky seems too dark. I would bump speed to 30 secs. Check your exposure. Then the next thing is simply to keep pushing the ISO to get a properly exposed shot. Depending on how dark the night is, you can push it up to ISO 4000 or 5000. Usually that should be enough to get good shots. Now if the moon is full and out, you won't get too many stars in the shot, but the moon makes a great fill light, and if it's bright enough, you might even see yourself backing down on the ISO to say 2000.

Thanks Jim. It sounds like the 17-40 f/4 may be all I'll need, and keep the SS at 30 sec or less. With respect to focus, I am surprised that it would be an issue, wide at f/4. I would think that I could just focus at infinity (fully counterclockwise on Canon focus ring I think) then maybe back it off a touch, or just keep it there. But I am a newbie at this for sure...

Yeah, the focusing trick to go to infinity and just back off a bit used to work great when we shot film back in the day, but rarely does that work anymore. If it will work with your setup that's great, but just to be safe before to set it up and focus your composition during the day and see where the focus actually sets itself up at. Either way, you just want to check it, because there is nothing worse then spending a couple of hours shooting at night only to realize when you get back that all of the shots are just slightly soft from being OOF.

The wider angle lens you shoot the longer the shutter can be open before seeing stars trailing. The larger the Apreture the more light you can capture during that timed exposure. The more light you can capture the better so you want the widest fastest lens you can buy.

Even with the widest of angles and largest of apertures you will still need to use a high ISO. The hardest part of this process is getting enough light to render the detail. A camera with low noise at the highest is ISO's will be critical.

Some of the best shots I have seen were taken with a D800 with a 14-24 f2.8 lens shot at 14mm wide open @f2.8 and ISO's between 3200-5000.
Dave Morrow is who shot them. He has a very nice tutorial on his method. It really helped me get my mind around the process.
Btw check what the moon phase will be. You don't want the moon up when you are going for the Milky Way shotshttp://www.davemorrowphotography.com/p/tutorial-shooting-night-sky.html?m=1

Jim is right, but the equation does hold and you do need to adjust for crop factor. My suggestion is that you take pics and review them before taking 100 shots. In many cases it will help to push it to the max, so you get more light....its just about how much star trail can you live with....a little...or none.
I like iso 400-800, it seems to be a good balance of capturing faint stars without getting much noise, but you might need to go higher to capture the scene you want. I usually do long exposures, so to get no trails I go with iso 2000 on my Nikon 7000 and 20 sec with the 18mm.
Good Luck!

I live in New Jersey and even the darkest of locations is not dark enough to get away from light pollution. I went out once with my D800. I accidently formatted the card before I downloaded my shots. I was able to save 5 shots. This is one of them. You can make out part of the milky way and plenty of stars.
Look at the link I posted above for better examples in Dave Morrows tutorial. He shoots in extremely dark locations to get those results. Make sure you look at the link in his tutorial to the clear sky forecast.
Here is my shot using his technique. You can see a meteor near the center. Aircraft near the bottom.
D800 14-24 f2.8. Shot at 14mm and F2.8, 25 second exposure ISO 2500. Mirror up, remote shutter. All in-camera noise reduction shut off.

If you want milky way shots, you do need a dark night, no moon, no light pollution and long exposures. Your terrestrial subjects will be black unless you use light painting. I personally don't care for that.

If you want the landscape to be naturally illuminated, you need some moonlight, a 1/2 moon will do a pretty good job, but you won't get a milky way. You can get pretty good stars without trails however.

I have the 17-40L. The 17-40 f4 is a great lens (light, wide, pretty good quality) but not a great night time shooting lens, because of f4. I have landed on zeiss 25 f2 as my prefered night lens. Alternatively Samyang 14 f2.8 if you live with the correctible distortion. Or 16-35 f2.8 if you don't mind heavier. lenrentals.com is your freind. 24-105 is another great lens for hiking - very versatile and not too heavy.

Samyang 14 2.8 and 24-105L might be a better choice, if you take only 2. Wide/fast and Long.

or

Samyang 14 f2.8 and 17-40L. Wide/fast and versatile. But limited to pretty short.

Thanks everyone. I purchased a 6D yesterday (yippee!). The 17-40 is next.

Looking at your responses and other posts, it seems like ISO 1600, f/2.8 and about 15-20 seconds works about right for moonless night skies. That type of exposure combo gives a lot of options if the 6D's high ISO performance is as good as they say. I hadn't considered a Samyang 14 f.2.8, but am now giving it some thought. Brutal distortion, I understand, but that's not an issue for this purpose, I should think.